Nitrous oxide emissions from a light-textured arable soil of North-Western Russia: effects of crops, fertilizers, manures and climate parameters

Direct nitrous oxide emissions from a light-textured arable soil typical of North-Western Russia and subject to different management systems were measured during three growing seasons (May-September) in 2003-2005. Cumulative fluxes varied between 0.26 ± 0.06 and 2.98 ± 1.56 kg N₂O-N ha⁻¹, with the lowest flux produced where no N was added as mineral fertilizers/manures or where green manure/low inputs of mineral fertilizer were used as a source of N. Highest cumulative fluxes were measured from the plots where high inputs of farmyard manure were used. Of the crops studied, potatoes produced the highest N₂O fluxes; this was attributed to the use of furrows, in which the soil tended to be more compact with higher water-filled pore space, making the soil more prone to denitrification than that in fields without furrows. The available N content of the soil at the start of each growing season was quite low and cumulative N₂O fluxes were significantly affected by N-fertilizer application within one growing season. However, for different growing seasons with highly changeable rainfall patterns and with different soil management for different crops, the quite high yearly correlation between N application and N₂O fluxes was much reduced.